[vtkusers] Bricking

[Kevin H. Hobbs]

On Mon, 2007-03-19 at 18:40 +0100, eugen wrote:
> 
> Sounds exactly what I'm looking for!!! I've read about streaming in VTK
> some time ago, but thought it was not applicable to volume rendering...
> 

I can see how it would seem inapplicable: all of the descriptions of
streaming talk about little block like pieces, while it would seem that
for volume rendering one would need all of the data visible through a
section of the screen in sort of an expanding square. The important bit
should be just the load a little, process a little, write a little part.

> Do you know for which tasks exactly streaming is supported? 

No. The rule goes something like "Tasks where each pixel of output
depends on the entire input do not tend to stream."

> Especially if
> VTK supports streaming for direct volume rendering?
> 

I had a volume rendering task that took more memory than is available on
my workstation. In the end I used ParaView on a cluster where each node
needs only a fraction of the data. I think the best I was able to do was
render the upper left piece of my output image over and over for each
streamed piece. The good news is that the memory usage was way lower.
I'll attach the code I have. I was trying to do pieces in parallel
instead of streamed. There's no guarantee I was even on the right track
though.

> My major problem is the memory limitation of videoboards. So I would like
> to split a dataset into smaller chunks and render them by texturemapping
> (with vtkVolumeTextureMapper3D). Do you say it is possible to set up a VTK
> pipeline in that way (with streaming) to visualize datasets larger than
> the VRAM can take in one piece?

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